1. Field of the Invention
The device of this invention resides in the field of devices that are positioned above a chimney flue to promote and increase the draft of smoke and air out of the chimney and more particularly relates to an improved ventilator which increases the updraft in a chimney irrespective of ambient air flow direction around the chimney.
2. History of the Prior Art
Typical of the prior art is U.S. Pat. No. 1,246,774 to Moyer patented in 1917. This patent shows a device with a cylindrical outer wall 12 surrounding a conical top member and a bottom member which receives the chimney flue therein, such bottom member spaced apart from the top member, forming circumferentially a spaced opening between the perimeters of the top and bottom members in communication with the flue with exhaust openings defined between such circumferentially spaced opening and the top and bottom of the cylindrical outer wall. In operation irrespective of the wind direction, the chimney flue will have an updraft of air because of the upwards suction pull created by the use of such a ventilator. In FIG. 3 of Moyer one can see that if the ambient air around the chimney is moving horizontally, suction is created between the circumferentially spaced openings and the cylindrical outer wall such that air is pulled out of the chimney flue and can pass out of the top and bottom exhaust openings. When ambient air currents are traveling downward or upwards as shown, respectively, in FIGS. 4 and 5, such air travels into the space between the cylindrical outer wall and the conical top and bottom members. In doing so, a suction is created through the circumferential openings, causing, again, an upwards travel of air in the flue whether the air is exhausted through the top or bottom of the exhaust openings. A similar device to that of Moyer is found in U.S. Pat. No. 1,354,623 to Redgate patented in 1920 which device uses a double tapered deflector disposed above the chimney surrounded by a cylindrical jacket 12 spaced away from the double tapered deflector forming exhaust openings. A similar air flow is created as seen in the drawings of FIGS. 4, 5 and 6 as that of Moyer.